CODEWITHSUNDEEP
c++linuxnetwork-programmingnetwork-protocolsnet-snmp
user1101467
user1101467

Reputation: 41

How to print an integer and Counter32 value in net-snmp

I founded this code that print string values and it works fine:

 add_mibdir("."); 
 pdu = snmp_pdu_create(SNMP_MSG_GET);

 read_objid(if_index, id_oid, &id_len);
 snmp_add_null_var(pdu, id_oid, id_len);    
 status = snmp_synch_response(sess_handle,pdu,&response);

 int count=1;
 for(vars = response->variables; vars; vars = vars->next_variable) 
  {
    if (vars->type == ASN_OCTET_STR) 
    {
        char *sp = (char *)malloc(1 + vars->val_len);
        memcpy(sp, vars->val.string, vars->val_len);
        sp[vars->val_len] = '\0';
        printf("value #%d is a string: %s\n", count++, sp);
        printf("%s\n",vars->val.string);
        free(sp);
}

  }

Example: for SNMPv2-SMI::mib-2.47.1.1.1.1.2.1012 = STRING: "GigabitEthernet Container", it returns "GigabitEthernet Container";

But I tried that for an integer value and it didn't work:

for(vars = response->variables; vars; vars = vars->next_variable)
    printf("%ld",(long int)vars->val.integer);//it returns large numbers;

Example: for SNMPv2-SMI::mib-2.17.2.11.0 = INTEGER: 1500, I want to return 1500 and for IF-MIB::ifOutBroadcastPkts.10103 = Counter32: 14011112 I want to return 14011112

If I use:

for(vars = response->variables; vars; vars = vars->next_variable)
    print_variable(vars->name, vars->name_length, vars);

it returns Counter32:12132, or INTEGER:12324, or STRING:Gi0/1 (but I want to parse this result and use it into some variables, without data type, for example: in var a to store 12132).

Thanks!

Upvotes: 4

Views: 4176

Answers (3)

Sam Sanders
Sam Sanders

Reputation: 31

I had the same problem I got it working with this...

      unsigned long val64;
      val64 = vars->val.counter64->high;
      printf("value #%lu is a COUNTER32:\n", val64);

Upvotes: 0

Gary
Gary

Reputation: 1525

In case anyone still has issues with this, I figured out an alternate mechanic that doesn't require parsing using net-snmp 5.7.3:

template<typename T>
static boost::shared_ptr< std::vector<T> > GetVector(std::string user_oid, struct snmp_session * snmp_session) {

    // Other Initialization ....

    char temp_buf[BUFSIZ];
    size_t temp_buf_len = BUFSIZ;
    bool orig_config_val_qp = netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICK_PRINT);
    bool orig_config_val_bv = netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_PRINT_BARE_VALUE);

    // Enforce this for correct output in snprint_variable functions
    netsnmp_ds_set_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICK_PRINT, 1);
    netsnmp_ds_set_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_PRINT_BARE_VALUE, 1);

    // oid conversion routines ...

    // Processing loop for response vars (similar to netsnmp/app/snmpbulkwalk.c) ...
    if (vars->type == ASN_OCTET_STR) 
    {
        temp_buf_len = BUFSIZ;
        snprint_variable(temp_buf, temp_buf_len, vars->name, vars->name_length, vars);
        result->push_back(boost::lexical_cast<T>(temp_buf));
    }
    // End Processing loop...

    // Restore configuration
    netsnmp_ds_set_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICK_PRINT, orig_config_val_qp);
    netsnmp_ds_set_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_PRINT_BARE_VALUE, orig_config_val_bv);

    return result;
}

This will leave the rest of your application configuration as it was and only spit out the value so you don't need to tokenize. I abbreviated the looping so that it focuses on the important aspects.

Upvotes: 2

Wes Hardaker
Wes Hardaker

Reputation: 22262

Well, you can always manipulate the data directly... The counter is stored in var->val.integer as you noted. But the faster way to get all of the LABEL: prefixes to be dropped from the output of print_variable is to set the NETSNMP_DS_LIB_QUICK_PRINT variable like so:

netsnmp_ds_set_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICK_PRINT, 1);

Which will drop the "Counter32:" prefix.

Upvotes: 0

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